1. Technical Field
The invention relates to a motor control device that controls a motor by monitoring a voltage between terminals of a motor and a vehicle brake hydraulic pressure control apparatus including the motor control device.
2. Related Art
In motor control devices, a rotation state of a motor is detected in order to control the number of motor revolutions and/or detect an abnormality in the motor. The rotation state of the motor can be determined based on a counter electromotive force of the motor which is obtained by detecting a voltage between terminals of the motor.
To obtain the counter electromotive force accurately, it is desirable to detect the voltage between the terminals at instant at which a current does not flow though the motor (a voltage is not applied). Thus, in the PWM (Pulse Width Modulation) control in which turning on/off of a motor current is repeated based on a duty ratio of the motor current, the voltage between the terminals of the motor is measured during an off period in which a voltage is not applied to the motor (JP 2001-10471 A).